Process of preparing hides for tanning



UNITED STATES PATENT OFFICE.

JAMES S. SWAN, OF MONGAUP VALLEY, NEW YORK.

PROCESS OF PREPARING HIDES FOR TANNING.

SPECIFICATION forming part of Letters Patent No. 237,630, dated February 8, 1881. Application filed September 8, 1880. (Specimens) To all whom it may concern:

Be it known that I, JAMES S.- SWAN, of Mongaup Valley, in the county of Sullivan and State of New York, have invented a new and useful Improvement in Processes of Preparing Hides for Tanning, of which the following is a specification.

In the manufacture of leather the hides are subjected to a lime-bath in order to loosen the hair, which hair is afterward removed by wellknown methods; but the hide then still contains much lime, which it becomes necessary to expel or neutralize before the beginning of the tanning process, or in the early stages thereof. Various processes are employed for this purpose, among which are hating, treating with acids, &c.; but all of them are in a measure objectionable, because of their liability to injure the hide or because of their interfering with or delaying the action of the tannic acid.

The object of this invention is to providea process whereby the lime may be neutralized or removed from the hide immediately after the unhairing process, or in any stage of the process of the manufacturing of the leather, and be neutralized or removed without injury or loss of weight to the hide, thereby leaving the said hide in the best condition for conversion into leather.

The process consists in subjecting the limed hide to a bath of alum dissolved in water in the proportions of two ounces. avoirdupois, of alum to one gallon of water, substituting the alum bath for hating or other processes for neutralizing or removing the lime, whereby the lime combines with the alum in solution, and, leaving the hide, forms an insoluble precipitate that falls to the bottom of the vessel in which the hides are unlimed.

This process is speedy and thorough in its operation, and does not destroy the gelatine or fiber of the hide nor cause any loss of weight.

I am aware that alum in the crystalline state has been used in curing furs and peltries, and that alum in solution with sulphuric acid and with sulphates of ammonia and soda has been used in the treatment of limed hides preparatory to converting them into leather; but I am not aware that limed hides have ever before been treated with a simple solution of alum in water for the purpose and with the effect of removing lime preparatory to tanning.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, 1s-

The improvement in the process of preparing hides for tanning, substantially as herein described, consisting in subjecting the limed hides to the action of an aqueous solution of alum, whereby the lime is removed or neutralized, as set forth.

JAMES SPENGER SWAN. Witnesses:

AUSTIN D. 0001:, WYNKOOP KIERSTED. 

